1. Field of the Invention
The invention is based on a pumping unit.
2. Description of the Prior Art
A pumping unit is already known from DE 101 15 866 A1, with a pump chamber in which a rotor is supported in rotary fashion and which is formed by a circumference wall and two end walls. The circumference wall is embodied on an annular collar of a pump part and on the inside, constitutes a track along which the sealing elements of a rotor roll. A powerful compressive loading acts on the track of the pump chamber and when the pump part is composed of plastic, can lead to a deformation of the pump chamber, for example of the track, which results in an increased friction or a jamming of the rotor.